Synthesis and Characterization of Novel Thienylpyridazine Derivatives

Recently, the exploration of thiophene π-conjugated systems functionalized with donor-acceptor groups has greatly expanded due to the increased interest in optoelectronic, photovoltaic and OLED applications. This type of molecules are highly targeted due to the easy tuning of the photophysical properties by small structural modifications.A few thienylpyridazines were synthesized as part of an on-going research directed to the development of donor-acceptor substituted heterocyclic systems for several optical (linear and nonlinear) and DSSCs applications.In this communication we report the synthesis and the photophysical characterization of novel thienylpyridazine derivatives, functionalized in position 3, with different donor groups (thiophene, pyrrole and N,N-dialkylphenylamine). The diazines were synthesized by Suzuki coupling of 3-bromo-6-(thiophen-2-yl)pyridazine with commercially available (hetero)aryl-boronic acids. On the other hand, precursor 3-bromo-6-(thiophen-2-yl)pyridazine was prepared by reaction of a thienylpyridazinone with POBr3. Acknowledgements: Thank are due to Fundação para a Ciência e Tecnologia (Portugal) and FEDER-COMPETE for financial support through the Centro de Química PEst-C/QUI/UI0686/2011 (F-COMP-01-0124-FEDER-022716) and a PhD grant to S. S. M. Fernandes (SFRH/BD/87786/2012). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT. We are also grateful to the Instituto da Educação of Universidade do Minho for providing the laboratory infrastructure necessary for the development of this work.